Uso de dientes bovinos como elección para trabajos de investigación en odontología / The use of bovine teeth as a choice for dental investigation papers

Los dientes animales de las diferentes especies (hu- mano, equino, cerdo, etc.) están constituidos histológi- camente por cuatro tejidos fundamentales. Ellos son: esmalte, dentina, cemento y pulpa dental. Su compo- sición, estructura, morfología y tamaño son disímiles para cada género. Según numerosas investigaciones, los dientes de bovino serían los de elección por ser de fácil obtención y por tener muy pocas, o ninguna, diferencias tanto a nivel macro como microscópico con respecto a los dientes humanos. El objetivo de la presente revisión es aportar información actualizada acerca de las características histológicas de los tejidos dentarios bovinos y profundizar el conocimiento de las similitudes y diferencias de los dientes bovinos y humanos dando soporte a otros estudios compa- rativos y promoviendo la utilización de las piezas dentarias bovinas en trabajos de investigación en odontología (AU)

The animal teeth of the different species (human, equine, pig, etc.) are histologically constituted by four fundamental tissues: enamel, dentin, cement and dental pulp. Their composition, structure, morphology and size are dissimilar for each gender. According to numerous investigations, bovine teeth would be the ones of choice because they are easy to obtain and have very few or no differences, both at the macro and microscopic levels, with respect to human teeth. The objective of this review is to provide updated information about the histological characteristics of bovine dental tissues and deepen the knowledge of the similarities and differences between bovine and human teeth, supporting other comparative studies and promoting the use of bovine dental pieces in research work in dentistry (AU)

El esmalte dental bovino como modelo experimental para la investigación en odontología: una revisión de la literatura / Bovine dental enamel as experimental model for research in dentistry. A literature review

El propósito de esta revisión bibliográfica es aportar información actualizada acerca de las características de los dientes bovinos en relación con su uso como sustitutos de dientes humanos en trabajos de investigación. De acuerdo con la información registrada, los dientes bovinos serían excelentes sustitutos de la dentición humana para la realización de ensayos de laboratorio con el esmalte dental como modelo experimental (AU)

The purpose of this bibliographic review is to provide updated information about the characteristics of bovine teeth to be used as substitutes for human teeth in dental research. According to the information recorded, bovine teeth appear to be excellent substitutes for human dentition for conducting laboratory tests, using dental enamel as an experimental model (AU)

Esmalte en terminología: concordancia y propuesta para terminologia anatomica, histologica y embryologica / Enamel in terminology: concordance and proposal for anatomical, histological and embryological terminology

El esmalte dental es una estructura considerada en Terminologia Anatomica, Histologica y Embryologica. Los términos incluidos relacionados a él presentan tres raíces asociadas: enamel, amelo y adamantino. El objetivo de este artículo es analizar la etimología de estas raíces y presentar propuestas en latín y español que unifiquen las denominaciones relacionadas al esmalte dentario. En la búsqueda fueron utilizaron diccionarios médicos, terminológicos y etimológicos. Los resultados obtenidos señalan tres orígenes diferentes para cada raíz: adamantino es un término grecolatino relacionado a la extrema dureza de una estructura; enamel tiene un origen anglo-normando y antiguo alto germánico relacionado a la acción de fundir, derretir, y el aspecto estético que esto produce en un material; y amelo, el cual en sí mismo está relacionado a la botánica mientras que el término completo ameloblasto, fue acuñado por un académico estadounidense. Si bien la etimología de adamantino y enamel señalan características de firmeza y estética, respectivamente, en el desarrollo de la propuesta se decidió mantener el término latinizado enamelum y su adjetivo enameleus, eliminando las otras dos raíces relacionadas al esmalte dentario. Se realizó la propuesta para los cambios en los términos del idioma latín y su traducción al español, acorde a los requerimientos de la FIPAT para Terminologia Anatomica, Histologica y Embryologica, con el fin de unificar la denominación de los términos asociados y derivados del esmalte dental, para fines académicos y de investigación.

Dental enamel is a structure considered in Anatomical, Histological and Embryological Terminology. The included terms related to it have three associated roots: enamel, amelo and adamantino. The objective of this article is to analyze the etymology of these roots and present proposals in Latin and Spanish that unify the denominations related to tooth enamel. In the search, medical, terminological and etymological dictionaries were used. The results obtained indicate three different origins for each root: adamantine is a Greco-Roman term related to the extreme hardness of a structure; enamel has an Anglo-Norman and ancient high Germanic origin related to the action of melting, melting, and the aesthetic appearance that this produces in a material; and amelo, which in itself is related to botany while the full term ameloblast, was coined by an American academic. Although the etymology of adamantine and enamel indicate characteristics of firmness and aesthetics, respectively, in the development of the proposal it was decided to maintain the Latinized term enamelum and its adjective enameleus, eliminating the other two roots related to dental enamel. The proposal was made for changes in the terms of the Latin language and its translation into Spanish, according to the requirements of the FIPAT for Anatomical, Histological and Embryological Terminology, in order to unify the denomination of the associated terms and derivatives of dental enamel, for academic and research purposes.

Unique Tooth Morphology and Prismatic Enamel in Late Cretaceous Sphenodontians from Argentina.

Mammals and reptiles have evolved divergent adaptations for processing abrasive foods. Mammals have occluding, diphyodont dentitions with taller teeth (hypsodonty), more complex occlusal surfaces, continuous tooth eruption, and forms of prismatic enamel that prolong the functional life of each tooth [1, 2]. The evolution of prismatic enamel in particular was a key innovation that made individual teeth more resilient to abrasion in early mammals [2-4]. In contrast, reptiles typically have thin, non-prismatic enamel, and shearing, polyphyodont dentitions with multi-cusped or serrated tooth crowns, multiple tooth rows, rapid tooth replacement rates, or batteries made of hundreds of teeth [5-9]. However, there are rare cases where reptiles have evolved alternative solutions to cope with abrasive diets. Here, we show that the combined effects of herbivory and an ancestral loss of tooth replacement in a lineage of extinct herbivorous sphenodontians, distant relatives of the modern tuatara (Sphenodon punctatus) [10], are associated with the evolution of wear-resistant and highly complex teeth. Priosphenodon avelasi, an extinct sphenodontian from the Cretaceous of Argentina, possesses a unique cone-in-cone dentition with overlapping generations of teeth forming a densely packed tooth file. Each tooth is anchored to its predecessor via a rearrangement of dental tissues that results in a novel enamel-to-bone tooth attachment. Furthermore, the compound occlusal surfaces, thickened enamel, and the first report of prismatic enamel in a sphenodontian are convergent strategies with those in some mammals, challenging the perceived simplicity of acrodont dentitions [11-15] and showcasing the reptilian capacity to produce complex and unusual dentitions.

Bandas de Hunter-Schreger: propuesta terminológica / Hunter-Schreger bands: terminological propose

Las Bandas de Hunter-Schreger (BHS), son bandas claras y oscuras, que se aprecian en el esmalte debido a la distínta curvatura de los prismas del esmalte, resultan ser ampliamente mencionadas en estudios, tanto odontológicos como antropológicos, mas no se ven reflejadas en Terminologia Histologica. El objetivo del presente trabajo fue realizar un análisis del término BHS, con el fin de proponerlo como nuevo término histológico, y así poder ser incluido en Terminologia Histologica por la Federative International Programme for Anatomical Terminology (FIPAT). Luego del análisis en textos de estudio y publicaciones científicas, proponemos en reemplazo del término BHS, por dos términos: diazone prismatica (diá del griego δι á 'a través de' y del griego zon(e) ζωνη 'faja', 'zona de la tierra') y parazone prismatica (pará gr. 'a lo largo de' y del griego zon(e) ζωνη 'faja', 'zona de la tierra'), definiendo así términos más descriptivos y que no utilizan epónimos, tal como lo establece la Terminología Internacional. Proponer nuevos términos que estén más acorde con los señalado por la International Federation of Associations of Anatomists (IFAA) y la propia terminología, presenta grandes desafíos; un término no sólo es una palabra que hace referencia a una estructura morfológica, sino que también es una unidad del lenguaje, que une a la comunidad morfológica en un solo lenguaje. Por lo cual proponemos que el término sea incluido por la FIPAT en próximas discusiones.

Hunter-Schreger Bands (HSB), are light and dark bands, which can be seen in the enamel due to the different curvature of the enamel prisms, they are widely mentioned in studies, both dental and anthropological, but are not reflected in Terminologia Histologica. The aim of the present work was to carry out an analysis of the HSB term, in order to propose it as a new histological term, and thus be able to be included in Terminologia Histologica by the Federative International Program for Anatomical Terminology (FIPAT). After the analysis in study texts and scientific publications, we propose in replacement of the term HSB, for two terms: diazone prismatica (diá of Greek δι á 'through' and of Greek zon(e) ζωνη 'strip', 'zone of the earth') and parazone prismatica (pará gr. 'along' and from the Greek zon(e) ζωνη 'strip', 'zone of the earth'), thus defining the most descriptive and noneponymous terms, as the International Terminology says. Propose new terms that are more in agreement with those indicated by the International Federation of Associations of Anatomists (IFAA) and the own terminology, presents great answers; A term is not only a word that refers to a morphological structure, but also a unit of language, which unites the morphological community in a single language. So we propose that the term sea included by the FIPAT in the next discussions.

Effects of bleaching using 10% carbamide peroxide with calcium or amorphous calcium phosphate on enamel mineral content and hardness / Asociación entre la severidad de Hipomineralización Incisivo-Molar (HIM) y lesiones cavitadas de caries en escolares

ABSTRACT This study evaluated enamel mineral content and surface microhardness before and after bleaching treatment using 10% carbamide peroxide (CP) containing calcium (Ca) or amorphous calcium phosphate (ACP). Thirty-six bovine slabs were randomly allocated into 3 groups (n = 12) according to bleaching treatment: G1 - Opalescence PF 10% (CP), G2 -NiteWhite ACP (CP+ACP), and G3 - Opalescence PF (10%) with calcium (CP+CA). The bleaching agent was applied on enamel surface for 6 h/day over a period of 21 days. Enamel surface was evaluated by Knoop microhardness (KNH) and micro energy-dispersive X-ray fluorescence spectrometry (p-EDXRF) at baseline and at after bleaching treatment. Data were statistically analyzed by repeated measures ANOVA and Tukey's test (a = 0.05). There was a significant decrease in microhardness after bleaching treatments for all study groups, but no difference between bleaching gels. There was no difference in the Ca/P ratio measured by p-EDXRF for all groups at the study times, but the mean value was lower in group CP+CA than in group CP+ACP. Group CP was similar to both CP+ACP and CP+CA. It can be concluded that enamel microhardness decreased after the bleaching process, regardless of the presence of calcium or ACP, but there was no significant change in the Ca/P ratio of enamel after bleaching for each tested gel. This indicates that the bleaching gels have erosive potential, causing softening of enamel without promoting surface loss, regardless of the presence of calcium of ACP ions.

RESUMO Este estudo avaliou o conteúdo mineral do esmalte e a microdureza superficial antes e após o tratamento clareador, utilizando peróxido de carbamida 10% (PC) contendo cálcio (Ca) ou fosfato de cálcio amorfo (ACP) em sua composigao. Trinta e seis espécimes de esmalte bovino foram alocados aleatoriamente em 3 grupos (n = 12) de acordo com os tratamentos clareadores: G1 - Opalescence PF 10% (CP), G2 -NiteWhite (CP+ACP); e G3 - Opalescence PF (10%) com cálcio (CP + CA). O agente clareador foi aplicado na superficie do esmalte por 6 h/dia por um periodo de 21 dias. A superficie do esmalte foi avaliada por microdureza Knoop (KNH) e espectrometria de fluorescencia de raios X micro-dispersiva (p-EDXRF) no inicio e após o tratamento clareador. Os dados foram analisados estatisticamente pelo teste ANOVA de medidas repetidas e Tukey (a = 0,05). Houve uma diminuigao significativa da microdureza após os tratamentos clareadores para todos os grupos estudados, mas nao houve diferenga entre os diferentes géis. Nao houve diferenga da relagao Ca/P mensurada por p-EDXRF para todos os grupos nos tempos estudados; no entanto, o grupo CP+CA apresentou menor valor comparado ao grupo CP+ACP. O grupo CP foi similar aos grupos CP+ACP e CP+CA. Portanto, pode-se concluir que houve redugao significativa da microdureza do esmalte após o clareamento, independente da presenga de cálcio ou APC na composigao dos géis, embora nao tenha havido alteragao significando na relagao Ca/P do esmalte após o clareamento. Isto indica um potencial erosivo dos géis clareadores, causando o amolecimento sem perda da estrutura do esmalte, independente da presenga dos íons cálcio e ACP.

Smile makeover by veneers ­ case report / Sonrisa mejorada por carillas dentales - reporte de un caso

Ceramic veneers have evolved in the last few years as an aesthetic restoration in the field of aesthetic dentistry. It is a conservative option as compared to full coverage crowns for improving the patients smile. Ceramic veneers are widely used for smile designing in patients with fluorosis, midline diastema, hypoplastic teeth, and peg shape laterals. Clinical relevance: This article highlights the smile designing of a young patient with fluorosis using ceramic veneers, which not only improves the smile of the patient but has positive psychological benefits.

Las carillas de cerámica han evolucionado en los últimos años como una restauración estética en el campo de la odontología estética. Es una opción conservadora para mejorar la sonrisa de los pacientes en comparación con las coronas de cobertura total. Las carillas de cerámica se usan ampliamente para el diseño de sonrisas en pacientes con f luorosis, diastema de la línea media, dientes hipoplásicos, o laterales en forma de clavija. Relevancia clínica: este artículo destaca el diseño de la sonrisa en un paciente joven con f luorosis utilizando carillas de cerámica, que no solo mejora la sonrisa del paciente sino que entrega beneficios psicológicos.

Shipping amphorae and shipping sheep? Livestock mobility in the north-east Iberian peninsula during the Iron Age based on strontium isotopic analyses of sheep and goat tooth enamel.

Animal mobility is a common strategy to overcome scarcity of food and the related over-grazing of pastures. It is also essential to reduce the inbreeding rate of animal populations, which is known to have a negative impact on fertility and productivity. The present paper shows the geographic range of sheep provisioning in different phases of occupation at the Iron Age site of Turó de la Font de la Canya (7th to 3rd centuries BC). Strontium isotope ratios from 34 archaeological sheep and goat enamel, two archaeological bones and 14 modern tree leaves are presented. The isotopic results suggest that sheep and goats consumed at the site were reared locally (within a few kilometres radius) during the whole period of occupation. The paper discusses the isotopic results in light of the socio-political structure of this period, as complex, strongly territorial societies developed during the Iron Age in the north-east Iberian Peninsula.

Uso de terminologia histologica en textos de histología oral: capítulo esmalte / Use of terminologia histologica in oral histology texts: enamel chapter

Para la enseñanza y aprendizaje de cualquier disciplina es clave el uso de una terminología clara y definida. Particularmente en el caso de Morfología, el rol de Programa Federativo Internacional de Terminología Anatómica (FIPAT) ha permitido avanzar a lograr la máxima unificación de la terminología asociada a esta disciplina, que considera múltiples variaciones lingüísticas en sus términos, dificultando su comprensión y difusión. Para que esta labor tenga un impacto más profundo en el uso correcto de la terminología internacional se debe articular un trabajo con los procesos de formación profesional que incorporan esta disciplina. El objetivo principal del presente estudio fue analizar la correcta utilización de Terminologia Histologica en los textos de estudios de Histología Oral, disponibles en Chile. Para este trabajo, se realizó un análisis de 4 textos de Histología Oral, dentro de los cuales se encontraban los 2 más utilizados por los estudiantes según las bases de datos de biblioteca de tres Universidades chilenas tanto públicas como privadas, además de 2 textos del área en idioma distinto al español (inglés y portugués). El análisis consistió, comparar el uso de los términos histológicos del capítulo "Esmalte" con los términos incluidos en Terminologia Histologica. Además de registrar errores en la denominación de términos tales como, eponimias, sinonimias y comparar con dos idiomas distintos al español, con el fin de descartar la traducción como problema principal. De los textos analizados el 100 % presentaba una mayor cantidad de términos histológicos en comparación con los 14 descritos por Terminologia Histologica, de los cuales solo 7 son nombrados en la totalidad de los textos. Se encontraron 59 términos para las distintas estructuras del esmalte entre todos los textos, de éstos, solo 15 son nombrados conjuntamente en los cuatro textos y 7 poseen un término asignado en FIPAT. Además son descritas múltiples estructuras que no están construidas bajo las consideraciones de la FIPAT, presentando eponímias y sinonimias. Llama la atención que la mayoría de los términos extraídos no poseen representación en Terminologia Histologica además del uso predominante de epónimos y sinónimos tanto entre los textos de estudio como dentro de los mismos encontrándose veinte términos con más de un nombre. A partir de estos resultados se sugiere realizar las modificaciones pertinentes además de proponer focos para mejorar el uso de Terminologia Histologica en la formación de los futuros profesionales.

For the teaching and learning of any discipline the use of a clear and defined terminology is key. Particularly in the case of Morphology, the role of the International Federative Program of Anatomical Terminology (FIPAT) has made it possible to advance towards the maximum unification of the terminology associated with this discipline, which considers multiple linguistic variations in its terms, hindering its understanding and dissemination. For this work to have a more profound impact on the correct use of international terminology, work must be articulated with the vocational training processes that incorporate this discipline. The main objective of the present study was to analyze the correct use of Terminologia Histologica in the texts of Oral Histology studies, available in Chile. For this work, an analysis of 4 texts of Oral Histology was carried out, among which were the 2 most used by students according to the library databases of three Chilean universities, both public and private, as well as 2 texts from the area. in a language other than Spanish (English and Portuguese). The analysis consisted in comparing the use of the histological terms of the "Enamel" chapter with the terms included in Terminologia Histologica. In addition to registering errors in the denomination of terms such as, eponymias, synonimies and compare with two languages ??other than Spanish, in order to rule out translation as the main problem. Of the texts analyzed, 100 % had a greater number of histological terms compared to the 14 described by Terminologia Histologica, of which only 7 are named in all the texts. 59 terms were found for the different enamel structures among all the texts, of these, only 15 are named together in the four texts and 7 have a term assigned in FIPAT. In addition, multiple structures are described that are not constructed under the considerations of the FIPAT, presenting eponyms and synonyms. It is noteworthy that most of the extracted terms do not have representation in Terminologia Histologica besides the predominant use of eponyms and synonyms either, between the various texts or within them, and twenty terms can be found with more than one name. From these results it is suggested that pertinent modifications be made, in addition to proposing foci to improve the use of Terminologia Histologica in the training of future professionals.

Effects of Er:YAG Laser Treatment on the Mineral Content and Morphology of Primary Tooth Enamel.

Objective: The aim of this study was to evaluate the mineral content and morphology of primary tooth enamel prepared using an Er:YAG laser at different power settings. Materials and methods: The buccal surfaces of 45 noncarious primary molars were assessed in this study. The surfaces were cleaned and the teeth were randomly divided into nine groups (n = 5 each) to evaluate the effects of Er:YAG laser treatment at different energy levels: 200 mJ, 2 Hz; 200 mJ, 3 Hz; 200 mJ, 10 Hz; 250 mJ, 2 Hz; 250 mJ, 3 Hz; 250 mJ, 10 Hz; 300 mJ, 2 Hz; 300 mJ, 3 Hz; and 300 mJ, 10 Hz. The mean percentage weight (wt%) of calcium (Ca), phosphorous (P), fluoride (F), magnesium (Mg), potassium (K), and sodium (Na) in the primary tooth enamel was calculated for each group using scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy before and after laser application. The enamel morphology was also evaluated using SEM. The obtained data were statistically analyzed by one-way analysis of variance and Tukey's honest significant difference test. Results: The mean wt% of Ca, P, and F in the enamel exhibited a significant change after laser treatment (p < 0.05); the wt% of Mg, K, and Na remained unchanged (p > 0.05). There was no association between the power setting of the laser and changes in the wt% of minerals in the enamel (p > 0.05). SEM showed that enamel irradiated at different energy levels exhibited a characteristic lava flow appearance, and more surface irregularities were observed with the 250-mJ setting than with the 200-mJ setting. Conclusions: Our findings suggest that the mineral content and morphology of the enamel of primary teeth are affected by Er:YAG laser irradiation.

Ultrasound assessment of soft tissue augmentation around implants in the aesthetic zone using a connective tissue graft and xenogeneic collagen matrix - 1-year randomised follow-up.

PURPOSE: A comparative, ultrasound evaluation of the thickness of keratinized mucosa (TKT) around implants one year after gingival augmentation (GA) by means of a connective tissue graft (CTG) and the xenogeneic collagen matrix (CMX). MATERIALS AND METHODS: A total of 75 bone level tapered implants (Conelog® Camlog) were inserted in 57 patients in the aesthetic area of both jaws. The patients were divided into 3 groups: control group I- without GA; group II- GA 3 months before implantation, and group III- GA 3 months after implantation. Groups II and III were divided into two subgroups depends on type of material used for GA: (a) CMX (Mucograft®, Geistlich Pharma AG) and (b) CTG. The patients underwent a clinical and ultrasound examination before, then after 3 and 12 months following GA respectively to evaluate TKT at two points using ultrasound equipment (Pirop®, Echoson). Point 1 was considered to be in the middle of the line connecting the cemento-enamel junction (CEJ) to the adjacent teeth, and point 2 on the mucogingival junction (MGJ). RESULTS: Three months after GA, the highest increase in gingival thickness was noted in group IIIb (point 1 - 0.95mm, 2 - 1.01mm). However, 12 months after GA the highest gingival thickness was observed in group IIb (point 1 - 1.76mm, 2 - 1.36m) and next IIIb (point 1 - 1.52mm, 2 - 1.15mm). CONCLUSIONS: Both CTG and Geistlich Mucograft® increased TKT, but higher values were noted using CTG augmentation before implantation. An ultrasonic device can be used as a non-invasive, reliable, and reproducible method for evaluating TKT.

Perikymata: a non-existent term: a scientific literature invention? Terminology analysis and proposal / Periquematíe: un término inexistente. ¿una invención de la literatura? Análisis de la terminología y propuesta

SUMMARY: The constant and gradual apposition of the enamel during odontogenesis forms different histological structures on the tooth, including the perikymata, which appear on the crown surface as ridges between two imbrication lines. Although they are enameldependent structures described in various scientific texts and publications, they are not included in the enamel-dependent histological terms published in the Terminologia Histologica. The aim of this study was to analyze the term perikymata from a linguistic point of view and propose it as a new histological term. The word perikymata is derived from the Greek words perí 'around'+ kyma, 'wave', introduced by Preiswerk in 1895. Although the term is descriptive in itself, concentrating only information about the structure in a single word, as the terminology establishes, this does not indicate its location. We propose the term perikymata enamelis (perikymata of the enamel) be added. Although proposing new terms that are more in line with the International Federation of Associations of Anatomists (IFAA) and its terminology poses great challenges, a term is not just a word that makes reference to a morphological structure, it is also a unit of language, a means of communication, which in this case unites the morphological community in a single language.

RESUMEN: La aposición constante y paulatina del esmalte, durante la odontogénesis, forman en el diente distintas estructuras histológicas, uno de ellas son los perikymatas; los cuales se presentan en la superficie coronaria, como rodetes o crestas bajas, entre dos líneas de imbricación. Si bien son estructuras dependientes del esmalte, descritas en múltiples textos y publicaciones científicas, estas no se encuentran dentro de los términos histológicos dependientes del esmalte, publicados en Terminologia Histologica. El objetivo del estudio fue realizar un análisis del término perikymata desde un punto de vista lingüístico y proponerlo como nuevo término histológico. El término perikymata deriva de las palabras griegas perí 'alrededor de' + kyma, 'onda', introducido por Preiswerk en 1895, si bien el término es descriptivo por si solo concentrando la información de la estructura en una sola palabra, tal como lo establece la terminología, este no indica su ubicación. Debido a lo anterior proponemos agregar el término perikymata enamelis (periquematíe del esmalte). Aunque proponer nuevos términos que estén más acorde con los señalado por la International Federation of Associations of Anatomists (IFAA) y la propia terminología, presenta grandes desafíos; un término no sólo es una palabra que hace referencia a una estructura morfológica, sino que también es una unidad del lenguaje, un vehículo de comunicación, que en este caso une a la comunidad morfológica en un solo lenguaje.

In Vivo Electron Paramagnetic Resonance Tooth Dosimetry: Dependence of Radiation-Induced Signal Amplitude on the Enamel Thickness and Surface Area of Ex Vivo Human Teeth.

In vivo L-band electron paramagnetic resonance tooth dosimetry is a newly developed and very promising method for retrospective biodosimetry in individuals who may have been exposed to significant levels of ionizing radiation. The present study aimed to determine the relationships among enamel thickness, enamel area, and measured electron paramagnetic resonance signal amplitude with a view to improve the quantitative accuracy of the dosimetry technique. Ten isolated incisors were irradiated using well-characterized doses, and their radiation-induced electron paramagnetic resonance signals were measured. Following the measurements, the enamel thickness and area of each tooth were measured using micro-focus computed tomography. Linear regression showed that the enamel area at each measurement position significantly affected the radiation-induced electron paramagnetic resonance signal amplitude (p < 0.001). Simulation data agreed well with this result. These results indicate that it is essential to properly consider enamel thickness and area when interpreting electron paramagnetic resonance tooth dosimetry measurements to optimize the accuracy of dose estimation.

Structural Analysis of Enamel in Teeth from Head-and-Neck Cancer Patients Who Underwent Radiotherapy.

OBJECTIVE: To analyze macroscopic, microscopic, and ultrastructural aspects of enamel from head-and-neck cancer patients submitted to radiotherapy. MATERIALS AND METHODS: Twenty sound extracted permanent molars were used and divided into 2 groups. The experimental group consisted of 10 molars from head-and-neck cancer patients submitted to radiotherapy with total doses that ranged from 50 to 70 Gy. Ten molars from patients who did not receive radiotherapy were matched with experimental-group samples by anatomic tooth group and comprised the control group. To perform a macroscopic analysis, standardized photos of different enamel faces were taken with a camera. Teeth were subjected to longitudinal cuts and hand polished to a final thickness of 0.1 mm. Enamel was analyzed under polarized light microscopy, and optical retardation values of birefringence were calculated in cervical, cusp, and occlusal pit areas. Subsequently, the same enamel areas were analyzed by scanning electron microscopy. Data from optical retardation values were statistically analyzed by 2-way ANOVA and Fisher's test (α < 0.05). RESULTS: No macroscopic differences were observed between the irradiated and control groups. Polarized light microscopy analysis revealed that cervical enamel exhibited darker areas characterized by discrete birefringence patterns compared to the control enamel. Optical retardation values were only significantly different in the cervical enamel of the irradiated and control groups (p < 0.0001). Scanning electron microscopy analysis revealed more evident interprismatic spaces in the cervical and outer cusp enamel of irradiated samples. CONCLUSIONS: Head-and-neck radiotherapy reduced optical retardation values of birefringence in cervical enamel, and the interprismatic spaces became more evident.

Enamel Thickness Determination by Optical Coherence Tomography: In vitro Validation.

Optical coherence tomography (OCT) has been introduced in dentistry as a nondestructive diagnostic imaging tool that does not utilize ionizing radiation. This study investigated the agreement between polarization-sensitive OCT (PS-OCT), microcomputed tomography (µ-CT), and histology for enamel thickness measurements. Human enamel samples were prepared and evaluated with µ-CT and PS-OCT and then sectioned and observed via digital transversal light microscopy. For all methods, a standard transversal section (b-scan) in each sample was selected, and the enamel thickness was measured at three predetermined positions using ImageJ analysis software. The results revealed significant high agreement between all tested methods, indicating the potential of PS-OCT as a clinical tool to effectively measure enamel thickness.

Histomorfología de la atrición en dientes temporarios / Histomorphology of attrition in temporary teeth

En la Facultad de Odontología de la Universidad Nacional del Nordeste, provincia de Corrientes, Argentina, se desarrolló un trabajo de investigación en el cual se estudiaron las características histológicas que presentaban el esmalte y la dentina de piezas dentarias temporarias bajo el proceso fisiológico de la atrición. Para dicho estudio, se obtuvieron 25 piezas dentarias temporarias de pacientes que concurrieron a la Cátedra de Odontopediatría para su atención. Las muestras fueron protocolizadas y clasificadas según la escala de desgaste dentario de Gerasimov modificada. Las piezas dentarias se procesaron mediante la técnica de desgaste para su observación al microscopio óptico, determinándose que el 48% de los casos el desgaste correspondía a grado I, el 36% al grado II y el resto al grado III. En los casos que afectó al esmalte únicamente se observó la sección de los prismas del esmalte. Cuando afectó esmalte y dentina en los grados II y III de la escala se observan tanto casos de dentina esclerótica como de trayectos muertos.

A research project was conducted at the School of Dentistry of the National University of the Northeast, Corrientes, Argentina. The histologic features of the enamel and dentin of temporary teeth under the physiological process of attrition were studied. For this study 25 temporary teeth were obtained from patients attending the Pediatric Dentistry Department for dental care. Samples were categorized and classified according to a modified version of Gerasimov’s tooth wear scale. The teeth were processed using the technical wear approach for observation through a microscope. It was determined that 48% of cases showed grade I wear, 36% grade II wear, and 16% grade III wear. In cases where only the dentin was affected, the section of the enamel prisms was observed. When both the enamel and the dentin were affected, reaching grade II and grade III wear levels, cases of both sclerotic dentin and dead tracts were observed.

Red Iron-Pigmented Tooth Enamel in a Multituberculate Mammal from the Late Cretaceous Transylvanian "Hateg Island".

Mammals that inhabit islands are characterized by peculiar morphologies in comparison to their mainland relatives. Here we report the discovery of a partial skull associated with the lower jaws of a Late Cretaceous (≈70 Ma) multituberculate mammal from the Carpathian "Hateg Island" of Transylvania, Romania. The mammal belongs to the Kogaionidae, one of the rare families that survived the Cretaceous-Paleogene mass extinction in Europe. The excellent preservation of this specimen allows for the first time description of the complete dentition of a kogaionid and demonstration that the enigmatic Barbatodon transylvanicus presents a mosaic of primitive and derived characters, and that it is phylogenetically basal among the Cimolodonta. Another peculiarity is the presence of red pigmentation in its tooth enamel. The red coloration is present on the anterior side of the incisors and on the cusps of most of the teeth. Energy-dispersive X-ray spectrometry (EDS) analysis reveals that the pigmented enamel contains iron, as in living placentals. Such a red pigmentation is known in living soricine shrews and many families of rodents, where it is thought to increase the resistance of the enamel to the abrasion that occurs during "grinding" mastication. The extended pattern of red pigment distribution in Barbatodon is more similar to that in eulipotyplan insectivores than to that in rodents and suggests a very hard diet and, importantly, demonstrates that its grasping incisors were not ever-growing. As inferred for other endemic Transylvanian vertebrates such as dwarf herbivorous dinosaurs and unusual theropod dinosaurs, insularity was probably the main factor of survival of such a primitive mammalian lineage relative to other mainland contemporaries of the Northern hemisphere.

Dental bleaching agents with calcium and their effects on enamel microhardness and morphology

Aim: To evaluate enamel microhardness and morphology after bleaching with hydrogen peroxide containing calcium in different concentrations. Methods: One hundred specimens of human teeth were ground and polished and had the initial microhardness evaluated. The specimens were randomly assigned into five groups (n=20): Group 1 - Control group (no treatment); Group 2 - Home Peroxide 6% (without calcium); Group 3 - Home Peroxide 7.5% (without calcium); Group 4 - White Class 6% (with calcium); Group 5 - White Class 7.5% (with calcium). For each group, the bleaching was performed according to the manufacturer's specifications. The specimens were bleached once a day for 5 days and subjected to pH cycling. Microhardness and scanning electron microscopy (SEM) analysis were performed before and after bleaching. Results: The results showed that groups submitted to bleaching treatment presented hardness loss compared to the control group. The group of 7.5% hydrogen peroxide with calcium showed a lower percentage of hardness loss in relation to other groups. Conclusion: Calcium in association with a higher hydrogen peroxide concentration may decrease microhardness changes on enamel.

The specific role of FAM20C in dentinogenesis.

FAM20C is an evolutionarily reserved molecule highly expressed in mineralized tissues. Previously we demonstrated that Sox2-Cre;Fam20C(fl/fl) mice, in which Fam20C was ubiquitously inactivated, had dentin and enamel defects as well as hypophosphatemic rickets. We also showed that K14-Cre;Fam20C(fl/fl) mice, in which Fam20C was specifically inactivated in the epithelium, had enamel defects but lacked hypophosphatemia and defects in the bone and dentin. These results indicated that the enamel defects in the Sox2-Cre;Fam20C(fl/fl) mice were independent of dentin defects and hypophosphatemia. To determine if the dentin defects in the Sox2-Cre;Fam20C(fl/fl) mice were associated with the enamel defects and hypophosphatemia, we crossed Fam20C(fl/fl) mice with Wnt1-Cre and Osr2-Cre transgenic mice to inactivate Fam20C in the craniofacial mesenchymal cells that form dentin and alveolar bone. The resulting Wnt1-Cre;Fam20C(fl/fl) and Osr2-Cre;Fam20C(fl/fl) mice showed remarkable dentin and alveolar bone defects, while their enamel did not show apparent defects. The serum FGF23 levels in these mice were higher than normal but lower than those in the Sox2-Cre;Fam20C(fl/fl) mice; they developed a mild type of hypophosphatemia that did not cause major defects in long bones. These results indicate that the dentin defects in the Sox2-Cre;Fam20C(fl/fl) mice were independent of the enamel defects.

Effect of adhesive remnant removal on enamel topography after bracket debonding

INTRODUCTION: At orthodontic treatment completion, knowledge about the effects of adhesive remnant removal on enamel is paramount. OBJECTIVE: This study aimed at assessing the effect of different adhesive remnant removal methods on enamel topography (ESI) and surface roughness (Ra) after bracket debonding and polishing. METHODS: A total of 50 human premolars were selected and divided into five groups according to the method used for adhesive remnant removal: high speed tungsten carbide bur (TCB), Sof-Lex discs (SL), adhesive removing plier (PL), ultrasound (US) and Fiberglass burs (FB). Metal brackets were bonded with Transbond XT, stored at 37oC for 24 hours before debonding with adhesive removing plier. Subsequently, removal methods were carried out followed by polishing with pumice paste. Qualitative and quantitative analyses were conducted with pre-bonding, post-debonding and post-polishing analyses. Results were submitted to statistical analysis with F test (ANOVA) and Tukey's (Ra) as well as with Kruskal-Wallis and Bonferroni tests (ESI) (P < 0.05). RESULTS: US Ra and ESI were significantly greater than TCB, SL, PL and FB. Polishing minimized Ra and ESI in the SL and FB groups. CONCLUSION: Adhesive remnant removal with SL and FB associated with polishing are recommended due to causing little damage to the enamel. .

INTRODUÇÃO: na finalização do tratamento ortodôntico, torna-se relevante o conhecimento da ação dos métodos de remoção do remanescente resinoso sobre o esmalte. OBJETIVO: o objetivo do estudo foi avaliar o efeito de métodos de remoção do remanescente de resina após a descolagem do braquete e do polimento na rugosidade (Ra) e topografia (ESI) do esmalte. MÉTODOS: foram selecionados 50 pré-molares humanos, divididos em cinco grupos, de acordo com o método empregado para a remoção da resina residual: broca carbide tungstênio em alta rotação (BCT), discos Sof-Lex (SL), alicate removedor de resina (AL), ultrassom (US) e pontas Fiberglass (PF). Braquetes metálicos foram colados com Transbond XT, armazenados a 37° por 24 horas antes da descolagem com alicate removedor de braquete, sendo aplicados posteriormente os meios de remoção e executado o polimento com pasta de pedra-pomes. Realizou-se análises qualiquantitativas, com avaliações antes da colagem dos braquetes, após a descolagem e após o polimento, sendo os valores obtidos submetidos à análise estatística com teste F (ANOVA), de Tukey (Ra) e testes de Kruskal-Wallis e Bonferroni (ESI) (p < 0,05). RESULTADOS: a Ra e o ESI do US foram significativamente maiores do que BCT, SL, AL e PF. O polimento reduziu a Ra e ESI dos grupos SL e PF. CONCLUSÃO: a remoção do adesivo resinoso com SL e PF associados ao polimento são os métodos mais indicados por ocasionarem as menores alterações do esmalte. .